Manchester United fly off for their American tour tomorrow with question marks still remaining over which new faces are going to be at Old Trafford next season.

The chances of Ronaldinho joining the Man U ranks appear to have receded as Barcelona upped the stakes in the contest to sign the midfielder, and his agent put a deadline of this weekend on the transfer being agreed.

They also have yet to agree personal terms with another Brazilian midfielder, Kleberson, who flew into the country yesterday for talks, nor a fee with his club Atletico Paranaense.

Ronaldinho's agent and brother Roberto Assis has delivered an ultimatum to Paris St Germain insisting that the transfer must be complete by this weekend.

Assis said: "It is a very complex transfer due to the amount of money that PSG are requesting, and also due to what the clubs are prepared to pay.

"We have given an ultimatum for the situation to be resolved by this weekend. That does not mean that Ronaldinho will stay with Paris. We are confident that the club will meet an agreement in the next 48 hours."

It's not just Brazilians driving Sir Alex Ferguson nuts - Argentinian midfielder Juan Sebastian Veron's future looks clouded after his move to Chelsea fell down due to the London side - owner Roman Abramovich's billions notwithstanding - baulking at his wage demands.

But it is Ronaldinho's future that will be concerning Man U most.

Barcelona have assumed pole position in the race to sign Ronaldinho from PSG with the Catalan side's &#xA3;21 million bid "completely superior" to Man U's offer according to the French club's president Francis Graille.

Graille said: "The offer from Manchester is not satisfactory to us. I think Barcelona will be successful at 30 million euros (&#xA3;21 million)."